I e always supported the Cosmic type to be added. The names for Sun and Moon bolster my hope they are eventually added. There's a lot that you can do with that with Pokemon centered on aliens, ufo'ms, black holes, stars, meteors, comets, supernovas, planets, satellites, etc. Retyping would include Deoyxs, Clefairy line, those alien poke line, solrock and lunatone, etc.
I also support a Cyber-type eventually being added that would be based on man-made or cybernetic based Pokemon. Some examples would include viruses, anti-viruses, pixels, hacking, A.I., computer chips, telescope, etc. Retyping could include the Porygon line and maybe Genesect.
I'm not too keen on adding Sound and Light but I wouldn't complain if they were. Sound-type can continue being apart of the Nortmal-type without much problems. The Light-type can also be attributed to both Fighting and Electric as well.